If a motor vehicle, such as a car, is involved in a collision, in which a front part of the vehicle hits a vulnerable road user, such as a pedestrian or a cyclist, the head of the vulnerable road user may impact on the bonnet of the vehicle. The vulnerable road user risks in that case to be severely injured. One parameter, which can affect the severity of the injury, is the fact that the bonnet, which is usually formed from thin metal sheet, would tend to bend, and deform on hard engine parts, such as an engine block, located in an engine compartment beneath the bonnet. In order to reduce the severity of such accidents, it is well-known to use a deployable bonnet, also called a pop-up hood. By raising the rear part of the deployable bonnet to a deployed position, the distance between the bonnet and the hard engine parts is increased, and thereby the consequences of such an impact are mitigated. The focus for using the deployable bonnet is hence to mitigate the consequences for the vulnerable road user being hit by the vehicle.
Moreover, there is also a risk for the vehicle to collide with an animal being on the road. Such a collision may occur when driving at high speed, e.g. in a rural area. If the animal is large, such as a moose, elk, reindeer, deer, kangaroo, cow or horse, a collision may be dangerous. The large animal usually has tall legs. There is therefore a risk that the torso of the large animal is thrown towards the windscreen of the vehicle. This may cause injury to a user of the vehicle and/or damages to the vehicle itself. A particular potentially dangerous case is when the torso of the large animal hits the vehicle close to the centre of the windscreen, since most of the impact energy in that case is received without any help from the A-pillars. If the torso instead hits the vehicle closer to an A-pillar, the A-pillar will help to receive the impact energy.
U.S. Pat. No. 7,997,375 B2 discloses a safety arrangement for a vehicle. In case of a collision with a large animal, the bonnet is slid upwards and rearwards to a position, wherein the bonnet shields the windscreen. However, by sliding the bonnet upwards and rearwards, the engine compartment, or at least a front portion of it, is unshielded. Further, in order to be able to shield the windscreen efficiently, the bonnet probably is rather stiff. This could cause a problem, in case the vehicle instead collides with a vulnerable road user, since it in that case is desirable that the bonnet is at least partly flexible and/or deformable to absorb the impact energy of the vulnerable road user.
The bonnet is in American English known as a hood, but herein the British English term bonnet is used.